A poorly chosen oligonucleotide can turn a well-planned experiment into weeks of troubleshooting. Failed PCR, weak hybridization, off-target amplification, and low cloning efficiency can all be the result of a improperly designed oligos. The right choice depends on the experiment, the target sequence, the chemistry required, and the downstream method. Oligo selection is a critical part of experimental design, not just a final ordering step. Oligo choice starts with matching t

PCR can be wonderfully reliable when every part of the reaction is working. It can also be frustrating when a gel shows a faint smear, missing band, extra bands, or no product at all. The good news is that most PCR problems come from a small set of causes: template quality, primer design, cycling conditions, reagent balance, or contamination. A useful PCR troubleshooting plan starts with the pattern you see. A clean but weak band points to a different issue from several unexp